Process for making ball-point writing instruments

ABSTRACT

IN THE MAKING OF A BALL-POINT WRITING INSTRUMENT, THE BALL-POINT IS INSERTED IN THE TIP OF THE INSTRUMENT BY DEFORMING THE METAL OF THE TIP BY HIGH FREQUENCY HAMMERING THEREBY SIMULTANEOUSLY FORMING AN INK CHAMBER.

Sept. 20, 1971 REGNAULT 3,605,246

PROCESS FOR MAKING BALL-POINT WRITING INSTRUMENTS Filed Feb. 14. 1969 row-h United States Patent Oflice 3,605,246 Patented Sept. 20, 1971 J Int. Cl. B231) 11/00 US. Cl. 29-441 7 Claims ABSTRACT OF THE DISCLOSURE In the making of a ball-point writing instrument, the ball-point is inserted in the tip of the instrument by deforming the metal of the tip by high frequency hammering thereby simultaneously forming an ink chamber.

The present invention is concerned with a new process which is particularly advantageous for making ball-carrying tips or writing tips for pencils or ball-point pens, such tips being generally called ball-points.

It is known that such tips must in order to give acceptable results comprise the following features which can be considered in the accompanying drawing which is an enlarged schematic axial section of a tip:

(1) There must be one or several ink feeds consisting in at least one feed channel 1. Theoretically this feed channel is centrally located.

(2) The ink must be distributed behind the ball B which necessitates the formation of openings 2 or secondary channels, the projecting walls 3 which define these open ings constituting the seat of the writing ball B. This rear seat is thus constituted of elements 3 which support the ball and a plurality of channels 2 for supplying ink to the ball. The formation of this part of the point is generally obtained in various manners: screw cutting, embossing, grooving, injection moulding, or stamping.

(3) An annular recess 4 allows the ball B to bathe in the ink along its entire circumference or spherical ring, the said circumference or spherical ring being located between the base seat and the lateral seat formed by the setting of lip 5 of the ball housing. This recess 4 can be considered an ink chamber.

It is conceived that the setting of lip 5 is vital to obtain proper operation of writing tips. It is necessary that the ball be maintained in its housing in such a way that it may:

(a) Project outside the housing while remaining imprisoned therein;

(b) Turn freely in its housing while moving on contact with a sheet of paper or any other writing surface;

(0) Transport ink with which it bathes along its circumference or spherical ring;

(4) Laminate this ink in a sufiicient film to make possible a constant and regular form writing during the en tire period of functioning of the tip, this laminating being obtained by the interstices or play provided between the ball and its lateral seat.

Various processes are used in order to obtain this result. There can be cited for example impact setting processes, pressure upset processes, mandrels which rotate by shrinking exerted by pressure, by edging rollers, and the like.

All these processes have for their purpose to form around the ball an envelope which has the features necessary for obtaining good hand-writing, that is to say deformation of a metal around the ball to obtain a shape such that the previously enumerated requirements are fulfilled.

A good number of processes which have been tried have not been suitable for the manufacture of ball points or tips on an industrial scale,

plicated therefore too costly or only giving mediocre results.

In effect, on the industrial scale the formation of the housing and its setting follow geometrical laws and characteristics which are well defined.

In effect, two processes are actually employed to set the ball and the ink chamber: a setting process by shock or pressure, a flanging process by flanging rolls or rollers.

The pressure setting process by means of a conical matrix can only give acceptable results if the supporting point of the ball has certain particular features, that is to say that the impact or pressure only form as much as it is necessary to form and that the mass of the metal to be set can respond in such a way that the play or interstices which remains between the lip or the lateral seat and the ball be exactly that which is necessary for the passage of the ink and for the laminating to obtain good writing. This process additionally is only useful if the metals used have characteristics such that their elastic limits give them a sufficient elastic return ability after they are shaped with impact. In the opposite case, it is indispensable to proceed with a calibration operation for the ball by spinning which tends to move away the partition forming the lateral seat. -It can be seen that this additional operation must be carried out with great precision which is rendered very difficult in practice.

In addition, this brutal deformation process causes cracks and other flaws in the metal which provide additional causes of poor functioning and premature wear in the writing tips.

According to the setting process by rolling, the attack or frictional contact of the flanging rollers on the peripheral lip takes place brutally and tends to twist the metal causing irregularities in the setting. There results an unequal play or interstice between the ball and its lateral seat which interferes with good operation in the writing tip.

The present invention proposes to remedy these drawbacks in a simple and economical manner. It has for its object a new process which makes it possible to work the metal in such a way that it is no longer necessary in order to obtain a result amenable to good handwriting, to have to make the conical ball short or long but relatively massive in order to obtain good setting. The great simplicity of the setting process of the invention makes possible the use of metals having various characteristics, this process making allowable a wide range of adjustment possibilities owing to the characteristics of ductility, deformation and elastic return of these metals.

According to an important characteristic of the invention, the operation of shrinking of the lip of the housing of the ball or of the setting of the said ball is achieved by high frequency hammering, the frequency of the impacts being variable along a wide range going from several blows/minute to ultra-sonic speeds.

This characteristic and other will appear more clearly from the following description.

There has been shown in a single figure of the drawings an example of the writing tip of a ball-point pen which can be obtained with the process of the invention.

There will be described now in a non-limiting manner the process of the invention. This process applies the possibility of deforming the metal in a progressive continuous and non brutal manner by a multiplication of relatively weak impacts in a single operation without a second operation.

The deformation of the metal by hammering or application of repeated high frequency impacts makes possible its progressive transformation. The structure of the metal is modified progressively during the operation and enables it to thus withstand without damage such processes being either. too coma relatively considerable deformation.

The hammering tool which will be denominated high frequency hammer can be actuated by various energy sources: compressed air, electricity, mechanical force, the essential being to have available high frequency impacting means, preferably adjustable, in order to adapt to the behavior of the various metals which can be used, the principle being the employment of high frequency hammering of relatively weak amplitude.

The hammer is equipped with a suitable crimping tool comparable to a cup set forming the head of a rivet. The shape of this tool will naturally differ according to the shape of the writing tip to be made and the nature of the metal used. The basic shape of this flanging tool being that necessary to obtain deformation of the metal around the ball in such a way that the required conditions above described for a good crimping and set of the ball be obtained.

Another advantage of this process is that by giving a suitable shape to the tool, there can be obtained, by deforming the metal, and this, simultaneously with the crimping operation, an ink chamber which has a con siderable capacity, thus improving the regularity of the ink feed to the ball. It is possible to make the capacity of this ink chamber vary according to need, by an adaptation of the reception cone of the ball, screw cutting or other, and/or by the shape of the crimping tool which is actuated by the high frequency hammer.

It has been indicated that the crimping by impact or by single pressure or by several impacts or pressures by successive passes along different posts can only give a valid result if the shape of the point makes it possible to secure it in a support forming a stack (anvil) which enables the metal to have a certain resiliency (resistance of the metal to impacts). It is certain that the classical point does not fullfill these requirements and that the piece worked in the air by this process would give a poor result, the metal not responding, the effect of the impact is partially lost and the effects are undesirable, they can have, in addition to an unwanted stacking along the length, a folding effect, the tool driving the piece outside a straight line. It is thus not possible to adopt for the long point a crimping system which uses impacts or pressure. It is for this reason that all the actually used processes for crimping points of the usual shape (that is to say outside points which employ short massive balls) are of the type which employ spinning by rolling, rotation of mandrels, impact or pressure being excluded.

The new hammering process by high frequency (numerous impacts of small amplitude and power) makes possible the progressive and correct deformation of the metal in the useful zone and in the desired shape without affecting other parts of the work piece.

This deformation of the metal has among other purposes to make it assume a regular shape which inscribes itself in the tool or crimping cup set in such a way that no unwanted sliding of the metal occurs.

By the high frequency hammering process, deformation of the metal being very progressive, there can be avoided the burrs or swellings which result in longitudinal and transversal breakages occasioned by too strong and brutal a reduction in section of the metal during a deformation.

On the contrary there is obtained a restructure of the metal.

Another aspect of the invention in effect is a modification of the metal.

The mechanical properties of different alloys dcpend upon the degree of cold drawing or cold rolling thereof evidenced by the formula:

It should be noted that from the starting state which is /2 hard and corresponds to IO ZU O of cold drawing, there is obtained by hammering a maximum cold drawing. It should be noted that at a certain stage of the operation, the metal no longer reacts, its maximum degree of transformation having been reached. The cold drawing is maximum, that is to say there has been obtained the maximum structural hardening. This is one of the goals sought, the hardness being maximum, the mechanical resistance for a given metal is reached. The advantage of the high frequency hammering process is that there is obtained this advantageous state in the metal without unwanted deformation.

Cold drawing increases the rupture load, the elastic limit and the hardness of the metals; it decreases the stretching, the reduction of area and the resilience. These characteristics are advantageous for the cone which receives the ball, which, in order to be efiicient, must hold the shape given to it. It is important that the metal no longer be deformable once it has attained its ideal shape. By the high frequency hammering, starting with a relatively soft metal, there is obtained, by giving to it the desired shape, a state of cold drawing which is allied to a maximum structural hardening giving the necessary resistance to undergo the deformation stresses exerted on the one hand, by the rotation of the ball, and on the other hand, the pressure exerted on the point by writing. It is conceived, that under these conditions the rear and lateral seats of the ball should have a maximum resistance to deformation and wear.

Another advantage of the process is that the working station can be readily included in a continuous manufacturing unit or machine transfer unit.

Another possibility consists in advantageously using the high frequency hammering system for the making of the point or writing tip: formation of the seat of the ball, the feed channels, etc. It suffices to provide the apparatus with tools which are suitable for the work to be carried out.

The frequency of the impacts can be variable in a very large range going from several impacts/minute to sonic or ultra-sonic speeds. This depends upon the details of the problem, that is to say for example: characteristics of the metal, type of operation, production rate.

The number of impacts (frequency) is generally given on a time basis of a minute.

By way of example, it is possible, starting with a number of impacts necessary to obtain a good result with a metal of given characteristics starting with a time of one minute, to know:

(1) Starting with the time necessary for the operation, the number of impacts which the tool must give per minute;

(2) The number of impacts given during the time selected for the operation, the latter being generally given by the cadence of the machine or the desired production.

By way of example:

A given work requiring 30 impacts of amplitude A in a minute requires a second 30 60=1,800 impacts of the same amplitude. The tool therefore operates at a cadence of 1,800 60:108,000 impacts/minute.

The advantage and the interest of the process of the invention appear from the foregoing.

As it goes without saying and as it has already been brought out from what precedes, the invention is in no way limited to those methods of utilization thereof neither to the particular embodiments of the various parts which have been more particularly pointed out but it encompasses on the contrary all variations thereof.

What is claimed is:

1. In a process for making a writing tip of the ballpoint type, comprising providing a writing ball and a metal housing having a rear seat for the ball, an annular chamber for supplying ink to the ball, an ink feed channel, a plurality of secondary channels in said seat for supplying ink from said feed channel to said chamber, and a lip portion surrounding the ball, the improvement whichv comprises applying to said tip portion a multiplicity of impacts of relatively low amplitude and at a frequency ranging from several impacts a minute to ultrasonic frequencies to progressively shrink the lip portion of the housing around the ball and thereby set the ball in the housing by said high frequency impacts.

2. Process according to claim 1, wherein said impacts are applied to said tip portion through a crimping tool.

3. Process according to claim 1, wherein the amplitude and frequency of said impacts are selected to effect maximum structural hardening of the metal of said lip portion.

4. Process according to claim 1, wherein said seat for said ball is also formed by high frequency impacts of relatively low amplitude.

5. Process according to claim 1, wherein said impacts are continuous and are carried out in a single operation.

6. Process according to claim 1, wherein said metal member is secured on a support during said impacts.

7. Process according to claim 1, wherein said metal member is suspended without support during said impacts.

References Cited UNITED STATES PATENTS 3,191,279 6/1965 Ashuroff 29200 3,252,214 5/1966 Fisher 29441 THOMAS H. EAGER, Primary Examiner 

